We investigated the compressional and shear velocities, V_P and V_S, of the HH1-phase by combining the inelastic x-ray scattering and x-ray diffraction experiments. In the pressure range of 64.7–79.6 GPa and at room temperature, the V_P and V_S were measured to be 9.66–11.05 and 4.9–6.4 km·s⁻¹, respectively. We employed a simplified model to quantitatively discuss the sound velocity differences between hydrous and anhydrous phase assemblages in the mid-lower mantle, revealing that the hydrous assemblage exhibits increased V_S and a reduced V_P/V_S ratio compared to its anhydrous counterpart. This suggests formation of seismic scatterers in the mid-lower mantle exhibiting high V_S anomalies may be related to the heterogeneous distribution of water. Moreover, the interpretation of a large V_P/V_S ratio as indicating the presence of water in the upper mantle and crust may not be applicable for detecting water in the lower mantle.

中文翻译：

---

含水富铁 HH1 相的声速：对下地幔地震非均质性的影响


我们通过结合非弹性 X 射线散射和 X 射线衍射实验研究了 HH1 相的压缩和剪切速度 V _P 和 V _S 。在 64.7–79.6 GPa 的压力范围内和室温下，测得的 V _P 和 V _S 分别为 9.66–11.05 和 4.9–6.4 km·s⁻ ¹ 。我们采用简化模型定量讨论了中下地幔中含水和无水相组合之间的声速差异，揭示了与无水组合相比，含水组合表现出增加的 V _S 和降低的 V _P /V _S 比。这表明在中下地幔中形成表现出高 V _S 异常的地震散射体可能与水的异质分布有关。此外，将大 V _P /V _S 比解释为表明上地幔和地壳中存在水，可能不适用于检测下地幔中的水。